Drop Weight and Drop Count Method: Principle: If a liquid is allowed to fall slowly through a capillary tube, the liquid first forms a drop at the tip of the capillary tube, which gradually increases in size and finally detaches […]
Capillary Rise Method: The capillary rise method is considered to be the most accurate way of measuring surface tension as the surface of the liquid is undisturbed during the measurement. However, the method is not suitable for measuring the interfacial […]
Interface is the boundary between two or more phases exist together. Several types of interface can exist depending on whether the two adjacent phases are in solid, liquid or gaseous state. LIQUID INTERFACES : Surface and Interfacial Tensions In the liquid […]
Sedimentation Technique: Equivalent diameter: Stokes’ diameter; frictional drag diameter—a sphere having an equivalent drag force to a particle of the same diameter in the same fluid at the same velocity. Range of analysis: 1 μm to about 200 μm. It […]
Dielectric constant: To properly discuss dipoles and the effects of solvation, one must understand the concept of dielectric constant. Placing a molecule in an electric field is one way to induce a dipole. In a capacitor (condenser), there are two parallel […]
A phase is the part whose physical and chemical properties are completely equal and homogenous. it is separated from other parts of the system by interfaces. A system containing water and its vapor is a two-phase system. An equilibrium mixture […]
Solubility of Liquid in Liquid: Frequently two or more liquids are mixed together in the preparation of pharmaceutical products (e.g. aromatic waters, spirits, elixirs, lotions, sprays, and medicated oils). Liquid–liquid systems can be divided into two categories according to the […]
Solubility of solids in liquids: Factors influencing solubility- Particle size (surface area) of drug particles ↓Particle size → ↑ surface area→ ↑Solubility. Log S/So = 2ϒv/2.303RTr So is the solubility of large particles S is the solubility of fine particles […]
Ideal and Real Solutions: Ideal solution: No change in the properties of the components, other than dilution, when they are mixed to form the solution. No heat is evolved or absorbed during the mixing process, The final volume of the […]
SOLVATION: The interaction between solute and solvent molecule which leads to stabilisation of solute species in the solution is called as solvation. The strength and nature of interaction between the solute molecule and solvent influences many properties of solute like […]